Anthony McJunkin and his brother, Branden McJunkin, 21, were in their apartment in the Seven Oaks complex in the 5900 block of Danny Kaye on the Northwest Side on early Friday, Aug. 31, 2012, when they began to squabble. Anthony said his brother took a $20 bill from a friend, so he shot him in the chest.

Anthony McJunkin told police it was just a “stupid argument,” and that he didn't mean to shoot his twin brother dead over $20.

McJunkin and his brother, Branden McJunkin, 21, were in their apartment in the Seven Oaks complex early Friday when they began to squabble. Anthony McJunkin said his brother took a $20 bill from a friend, so he shot him in the chest.

“I didn't mean to do it,” Anthony McJunkin told police.

Neighbors at the Northwest Side apartment complex said they awoke when the victim began beating on their doors. He was having difficulty breathing.

The twins' mother, Tracy McJunkin, spoke about her sons during a brief interview Friday afternoon in the living room of their home in the Enclave at Laurel Canyon subdivision on the Northwest Side.

She said the fraternal twins had been living together at the apartment in the 5900 block of Danny Kaye while Anthony attended the College of Health Care Professions and worked at a Quiznos restaurant. His twin was unemployed.

Shortly into the interview, her husband, John McJunkin IV, emerged from upstairs and politely asked reporters to end the conversation and leave.

While Anthony and Branden had arrest records, the charges were misdemeanors and nothing that would necessarily predict deadly violence.

The incidents for both occurred in late 2008 when the brothers were 17, according to public records. Branden McJunkin pleaded no contest to an assault charge — records show he hit another man in the head.

His brother was charged in a separate incident for evading arrest, public records show.

Both received probation and each completed his term, but court documents show Anthony McJunkin was facing a revocation of his probation because of smoking pot, failing to complete his community service hours, not checking in with his probation officer and not getting his GED.

By December 2010, however, he had met all of the requirements in his deferred adjudication plea and his case was dismissed, according to court records.

Information wasn't available on how long the brothers lived together at the apartment. In court documents for a temporary restraining order and divorce filed in November by Tracy McJunkin against her husband, she lists Branden McJunkin as living with her near Helotes.

Anthony McJunkin isn't mentioned.

Tracy McJunkin said her husband verbally threatened her and her children; she believed he was having a bad reaction to anti-rejection medication after a liver transplant, according to the documents.

The restraining order was granted for 90 days and expired in mid-February. The divorce also was dismissed, records show.

The special bond between twins can make violent episodes especially traumatic, according to human behavior specialists who study twins.

Some research has shown twins experience greater grief when one dies than the death of any other relative, except for a spouse.